Solid-state image pickup device, method for manufacturing solid-state image pickup device, and camera

ABSTRACT

A solid-state image pickup device including a plurality of pixels on a light-receiving surface, photodiodes disposed on the light-receiving surface of a semiconductor substrate while being partitioned on the pixel basis, signal transferring portions which are disposed on the semiconductor substrate and which read signal charges generated and stored in the photodiodes or voltages corresponding to the signal charges, insulating films disposed on the semiconductor substrate while covering the photodiodes, concave portions disposed in the insulating films, pad electrodes disposed on the insulating films, a passivation film which covers inner walls of the concave portions, which is disposed on the pad electrodes, and which has a refractive index higher than that of silicon oxide, and a core layer which is disposed on the passivation film while being filled in the concave portions and which has a refractive index higher than that of silicon oxide.

RELATED APPLICATION DATA

This application is a continuation of U.S. patent application Ser. No.11/950,680, filed Dec. 5, 2007, the entirety of which is incorporatedherein by reference to the extent permitted by law. The presentinvention contains subject matter related to Japanese PatentApplications JP 2006-332421 and JP 2007-106900 filed in the JapanesePatent Office on Dec. 8, 2006 and Apr. 16, 2007, respectively, theentire contents both of which are incorporated herein by reference tothe extent permitted by law.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a solid-state image pickup device, amethod for manufacturing the solid-state image pickup device, and acamera. In particular, the present invention relates to a solid-stateimage pickup device, in which pixels having diodes are arranged in amatrix on a light-receiving surface, the method for manufacturing thesolid-state image pickup device, and a camera provided with thesolid-state image pickup device.

2. Description of the Related Art

For example, in the configuration of a solid-state image pickup device,e.g., a CMOS sensor or a CCD element, light is allowed to enterphotodiodes (photoelectric conversion portion) disposed on a surface ofa semiconductor substrate, and an image signal is obtained on the basisof signal charges generated in the photodiodes.

In the CMOS sensor, for example, pixels are arranged in atow-dimensional matrix on a light-receiving surface, and a photodiode isdisposed on the pixel basis. Signal charges generated and stored in eachphotodiode during reception of light are transferred to a floatingdiffusion by driving a CMOS circuit, and the signal charges areconverted to signal voltages so as to be read.

In the CCD element, for example, pixels are arranged in atow-dimensional matrix on a light-receiving surface, and a photodiode isdisposed on the pixel basis, as in the CMOS sensor. Signal chargesgenerated and stored in each photodiode during reception of light aretransferred through a CCD vertical transfer line and a horizontaltransfer line so as to be read.

In the above-described solid-state image pickup device, e.g., a CMOSsensor, for example, the above-described photodiodes are disposed on asurface of a semiconductor substrate. An insulating film of, forexample, silicon oxide, is disposed as a layer covering the photodiodes.Wiring layers are disposed in the insulating film except photodioderegions so as to avoid hindering the entrance of light into thephotodiodes.

However, regarding the above-described solid-state image pickup device,the area of the light-receiving surface has been reduced as elementshave been made finer. Accompanying this, a problem occurs in that therate of incident light decreases and the sensitivity characteristicsdeteriorate.

A structure, in which light is condensed by using an on-chip lens, aninterlayer lens, or the like, has been developed as a countermeasureagainst this. In particular, a solid-state image pickup device has beendeveloped, in which an optical waveguide for guiding the light incidentfrom the outside to a photodiode has been disposed in the insulatingfilm above the photodiode.

Japanese Unexamined Patent Application Publication Nos. 2003-224249 and2003-324189 disclose solid-state image pickup devices in which concaveportions are disposed in insulating films above photodiodes, the concaveportions are filled with silicon nitride that is a substance having arefractive index higher than the refractive index of silicon oxide(hereafter referred to as high-refractive index substance) and, thereby,optical waveguides for guiding the incident light to the photodiodes aredisposed.

Japanese Unexamined Patent Application Publication No. 2004-207433discloses a solid-state image pickup device in which a concave portionof an insulating film above a photodiode is filled with a siliconnitride film and a polyimide film and, thereby, an optical waveguide isdisposed.

Japanese Unexamined Patent Application Publication No. 2006-190891discloses a solid-state image pickup device in which an insulating filmincluding a diffusion-preventing layer in the layer, a concave portionis disposed in a portion of the insulating film, the portion being abovea photodiode, in such a way that the diffusion-preventing layer isremoved, and the concave portion is filled with a silicon oxide film.

On the other hand, Japanese Unexamined Patent Application PublicationNo. 2006-222270 discloses a solid-state image pickup device, in which aconcave portion of an insulating film above a photodiode is filled witha TiO-dispersion type polyimide resin and, thereby, an optical waveguideis disposed.

SUMMARY OF THE INVENTION

However, the above-described solid-state image pickup device, in whichthe optical waveguide for guiding the incident light to the photodiodeis disposed in the insulating film above the photodiode, has a problemin that the process becomes complicated by disposition of the opticalwaveguide.

The heat resistance may deteriorate depending on the materialconstituting the optical waveguide.

Regarding a solid-state image pickup device including an opticalwaveguide, it is desirable to avoid the production process from becomingcomplicated due to disposition of the optical waveguide.

Furthermore, it is desirable to easily produce an optical waveguideprovided with the high heat resistance and the high refractive index.

A solid-state image pickup device according to an embodiment of thepresent invention is a solid-state image pickup device having aplurality of pixels integrated on a light-receiving surface, the deviceincluding photodiodes which are disposed in pixel regions serving as theabove-described light-receiving surface of a semiconductor substrate andwhich are partitioned on the above-described pixel basis, signaltransferring portions which are disposed on the above-describedsemiconductor substrate and which read signal charges generated andstored in the above-described photodiodes or voltages corresponding tothe above-described signal charges, insulating films disposed on theabove-described semiconductor substrate while covering theabove-described photodiodes, concave portions disposed in the portionsof the above-described insulating films above the photodiodes, padelectrodes disposed as layers on the above-described insulating films inpad electrode regions, a passivation film which covers inner walls ofthe above-described concave portions, which is disposed as a layer abovethe pad electrodes, and which has a refractive index higher than therefractive index of silicon oxide, and a core layer which is disposed asa layer on the above-described passivation film while being filled inthe above-described concave portions and which has a refractive indexhigher than the refractive index of silicon oxide.

The above-described solid-state image pickup device according to anembodiment of the present invention is a solid-state image pickup devicehaving a plurality of pixels integrated on the light-receiving surface.The photodiodes are disposed in the pixel regions serving as thelight-receiving surface of the semiconductor substrate, and arepartitioned on the pixel basis. The signal transferring portions aredisposed for reading signal charges generated and stored in thephotodiodes or voltages corresponding to the signal charges. Theinsulating films are disposed on the semiconductor substrate whilecovering the photodiodes.

The concave portions are disposed in the portions of the insulatingfilms above the photodiodes. On the other hand, the pad electrodes aredisposed as layers on the insulating films in pad electrode regions. Thepassivation film having a refractive index higher than the refractiveindex of silicon oxide is disposed as a layer above the pad electrodes,while covering inner walls of the above-described concave portions.Furthermore, the core layer having a refractive index higher than therefractive index of silicon oxide is disposed as a layer on thepassivation film while being filled in the concave portions.

A solid-state image pickup device according to an embodiment of thepresent invention is a solid-state image pickup device having aplurality of pixels integrated on a light-receiving surface, the deviceincluding photodiodes which are disposed in pixel regions serving as theabove-described light-receiving surface of a semiconductor substrate andwhich are partitioned on the above-described pixel basis, signaltransferring portions which are disposed on the above-describedsemiconductor substrate and which read signal charges generated andstored in the above-described photodiodes or voltages corresponding tothe above-described signal charges, insulating films disposed on theabove-described semiconductor substrate while covering theabove-described photodiodes, concave portions disposed in the portionsof the above-described insulating films above the photodiodes, and acore layer which is disposed while being filled in the above-describedconcave portions, and which contains an inorganic substance and a metaloxide having the heat resistance higher than the heat resistance of aTiO-dispersion organic resin.

The above-described solid-state image pickup device according to anembodiment of the present invention is a solid-state image pickup devicehaving a plurality of pixels integrated on the light-receiving surface.The photodiodes are disposed in the pixel regions serving as thelight-receiving surface of the semiconductor substrate, and arepartitioned on the pixel basis. The signal transferring portions aredisposed for reading signal charges generated and stored in thephotodiodes or voltages corresponding to the signal charges. Theinsulating films are disposed on the semiconductor substrate whilecovering the photodiodes.

The concave portions are disposed in the portions of the insulatingfilms above the photodiodes. The core layer is disposed while beingfilled in the concave portions, and contains the inorganic substance andthe metal oxide having the heat resistance higher than the heatresistance of the TiO-dispersion organic resin.

A method for manufacturing a solid-state image pickup device accordingto an embodiment of the present invention is a method for manufacturinga solid-state image pickup device having a plurality of pixelsintegrated on a light-receiving surface, the method including the stepsof forming photodiodes in pixel regions serving as the above-describedlight-receiving surface of a semiconductor substrate, the photodiodesbeing partitioned on the above-described pixel basis, and signaltransferring portions for reading signal charges generated and stored inthe above-described photodiodes or voltages corresponding to theabove-described signal charges, forming insulating films on theabove-described semiconductor substrate, the insulating films coveringthe above-described photodiodes, forming concave portions in theportions of the above-described insulating films above the photodiodes,forming pad electrodes as layers on the above-described insulating filmsin pad electrode regions, forming a passivation film as a layer abovethe pad electrodes, the passivation film covering inner walls of theabove-described concave portions and having a refractive index higherthan the refractive index of silicon oxide, and forming a core layer asa layer on the above-described passivation film, the core layer having arefractive index higher than the refractive index of silicon oxide andbeing filled in the above-described concave portions.

The above-described method for manufacturing a solid-state image pickupdevice according to an embodiment of the present invention is a methodfor manufacturing a solid-state image pickup device having a pluralityof pixels integrated on the light-receiving surface. The photodiodes areformed in pixel regions serving as the light-receiving surface of thesemiconductor substrate, the photodiodes being partitioned on the pixelbasis. The signal transferring portions for reading signal chargesgenerated and stored in the photodiodes or voltages corresponding to thesignal charges are formed.

Subsequently, the insulating films covering the photodiodes are formedon the semiconductor substrate. The concave portions are formed in theportions of the insulating film above the photodiodes. The padelectrodes are formed as layers on the insulating films in the padelectrode regions.

The passivation film is formed as a layer on the pad electrodes, thepassivation film covering inner walls of the concave portions and havinga refractive index higher than the refractive index of silicon oxide.The core layer is formed as a layer on the passivation film, the corelayer having a refractive index higher than the refractive index ofsilicon oxide and being filled in the concave portions.

A method for manufacturing a solid-state image pickup device accordingto an embodiment of the present invention is a method for manufacturinga solid-state image pickup device having a plurality of pixelsintegrated on a light-receiving surface, the method including the stepsof forming photodiodes in pixel regions serving as the above-describedlight-receiving surface of a semiconductor substrate, the photodiodesbeing partitioned on the above-described pixel basis, and signaltransferring portions for reading signal charges generated and stored inthe above-described photodiodes or voltages corresponding to theabove-described signal charges, forming insulating films on theabove-described semiconductor substrate, the insulating films coveringthe above-described photodiodes, forming concave portions in theportions of the above-described insulating films above the photodiodes,forming a core layer by filling the above-described concave portionswith an inorganic substance, the core layer having the heat resistancehigher than the heat resistance of a TiO-dispersion organic resin, andion-implanting a metal oxide into the above-described core layer.

The above-described method for manufacturing a solid-state image pickupdevice according to an embodiment of the present invention is a methodfor manufacturing a solid-state image pickup device having a pluralityof pixels integrated on the light-receiving surface. The photodiodes areformed in pixel regions serving as the light-receiving surface of thesemiconductor substrate, the photodiodes being partitioned on the pixelbasis. The signal transferring portions for reading signal chargesgenerated and stored in the photodiodes or voltages corresponding to thesignal charges are formed.

Subsequently, the insulating films covering the photodiodes are formedon the semiconductor substrate. The concave portions are formed in theportions of the insulating film above the photodiodes.

The core layer is formed by filling the concave portions with theinorganic substance and ion-implanting the metal oxide into the corelayer, the core layer having the heat resistance and the refractiveindex higher than those of the TiO-dispersion organic resin.

A camera according to an embodiment of the present invention includes asolid-state image pickup device having a plurality of pixels integratedon a light-receiving surface, an optical system for leading incidentlight to an image pickup portion of the above-described solid-stateimage pickup device, and a signal processing circuit for processingoutput signals from the above-described solid-state image pickup device,wherein the above-described solid-state image pickup device having aplurality of pixels integrated on the light-receiving surface includesphotodiodes disposed in pixel regions serving as the above-describedlight-receiving surface of a semiconductor substrate, the photodiodesbeing partitioned on the above-described pixel basis, signaltransferring portions which are disposed on the above-describedsemiconductor substrate and which read signal charges generated andstored in the above-described photodiodes or voltages corresponding tothe above-described signal charges, insulating films disposed on theabove-described semiconductor substrate while covering theabove-described photodiodes, concave portions disposed in the portionsof the above-described insulating films above the photodiodes, padelectrodes disposed as layers on the above-described insulating films inpad electrode regions, a passivation film which covers inner walls ofthe above-described concave portions, which is disposed as a layer abovethe pad electrodes, and which has a refractive index higher than therefractive index of silicon oxide, and a core layer which is disposed asa layer on the above-described passivation film while being filled inthe above-described concave portions and which has a refractive indexhigher than the refractive index of silicon oxide.

The above-described camera according to an embodiment of the presentinvention includes the solid-state image pickup device having aplurality of pixels integrated on the light-receiving surface, theoptical system for leading incident light to the image pickup portion ofthe solid-state image pickup device, and the signal processing circuitfor processing output signals from the solid-state image pickup device,wherein the solid-state image pickup device has the above-describedconfiguration.

In the configuration of the solid-state image pickup device according toan embodiment of the present invention, the concave portions aredisposed in the insulating films above the photodiodes, the insulatingfilms being disposed as layers on the photodiodes, the concave portionsare filled with the high-refractive index substance so as to constitutethe optical waveguide, and the passivation film disposed as a layer onthe pad electrodes is also used as the high-refractive index substanceto be filled in the concave portions. Therefore, the configuration canbe produced by a simpler process even when the optical waveguide isdisposed.

Regarding the solid-state image pickup device according to an embodimentof the present invention, the optical waveguide provided with the highheat resistance and the high refractive index can be obtained.

In the method for manufacturing a solid-state image pickup deviceaccording to an embodiment of the present invention, the passivationfilm disposed as the layer on the pad electrodes is also used as thehigh-refractive index substance to be filled in the concave portions.Therefore, the production can be performed by a simpler process evenwhen the optical waveguide is disposed.

The method for manufacturing a solid-state image pickup device accordingto an embodiment of the present invention can produce the opticalwaveguide provided with the high heat resistance and the high refractiveindex.

Regarding the camera according to an embodiment of the presentinvention, in the solid-state image pickup device constituting thecamera, the passivation film disposed as the layer on the pad electrodesis also used as the high-refractive index substance filled in theconcave portions. Therefore, the configuration can be produced by asimpler process even when the optical waveguide is disposed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of a solid-state image pickup deviceaccording to a first embodiment of the present invention;

FIG. 2 is a schematic layout diagram of a pixel portion of thesolid-state image pickup device according to the first embodiment of thepresent invention;

FIG. 3 is a schematic sectional view for explaining a route of lightincident on a photodiode of the solid-state image pickup deviceaccording to the first embodiment of the present invention;

FIGS. 4A to 4G are schematic diagrams showing examples of the shapes ofconcave portions of the solid-state image pickup device according to thefirst embodiment of the present invention;

FIGS. 5A and 5B are sectional views showing a production process of amethod for manufacturing the solid-state image pickup device accordingto the first embodiment of the present invention;

FIGS. 6A and 6B are sectional views showing a production process of amethod for manufacturing the solid-state image pickup device accordingto the first embodiment of the present invention;

FIG. 7 is a sectional view showing a production process of a method formanufacturing the solid-state image pickup device according to the firstembodiment of the present invention;

FIG. 8 is a sectional view showing a production process of a method formanufacturing the solid-state image pickup device according to the firstembodiment of the present invention;

FIG. 9 is a sectional view showing a production process of a method formanufacturing the solid-state image pickup device according to the firstembodiment of the present invention;

FIG. 10 is a sectional view showing a production process of a method formanufacturing the solid-state image pickup device according to the firstembodiment of the present invention;

FIG. 11 is a sectional view showing a production process of a method formanufacturing the solid-state image pickup device according to the firstembodiment of the present invention;

FIG. 12 is a sectional view of a solid-state image pickup deviceaccording to a second embodiment of the present invention;

FIG. 13 is a sectional view showing a production process of a method formanufacturing the solid-state image pickup device according to thesecond embodiment of the present invention;

FIG. 14 is a sectional view showing a production process of a method formanufacturing the solid-state image pickup device according to thesecond embodiment of the present invention;

FIG. 15 is a sectional view showing a production process of a method formanufacturing the solid-state image pickup device according to thesecond embodiment of the present invention;

FIG. 16 is a sectional view showing a production process of a method formanufacturing the solid-state image pickup device according to thesecond embodiment of the present invention; and

FIG. 17 is a schematic configuration diagram of a camera according to athird embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A solid-state image pickup device according to an embodiment of thepresent invention, a method for manufacturing the same, and anembodiment of a camera including the solid-state image pickup devicewill be described below with reference to drawings.

First Embodiment

FIG. 1 is a schematic sectional view of a CMOS sensor, which is asolid-state image pickup device according to an embodiment of thepresent invention and which includes a plurality of pixels integrated,and a pixel region R_(PX) and a pad electrode region R_(PAD) are shown.

For example, in the pixel region R_(PX) serving as a light-receivingsurface, an n-type charge-storage layer 11 and a p⁺-type surface layer12, which is a surface layer of the n-type charge-storage layer, aredisposed on a pixel basis in a p-well region 10 of a semiconductorsubstrate, a photodiode PD is constructed by pn junction and,furthermore, a gate insulating film 13 and a gate electrode 14 aredisposed adjacently to the photodiode PD on the semiconductor.

For example, a signal transferring portion, e.g., a floating diffusionand a CCD charge transfer line, for reading signal charges generated andstored in the photodiodes PD or voltages corresponding to the signalcharges is disposed on the above-described semiconductor substrate, andsignal charges are transferred by applying a voltage to the gateelectrode 14.

An insulating film covering the photodiode PD is disposed on thesemiconductor substrate. The insulating film is constructed bylaminating a first insulating film 15, a second insulating film 16, athird insulating film 17, a fourth insulating film 21, a fifthinsulating film 22, a sixth insulating film 26, a seventh insulatingfilm 27, and an eighth insulating film 31, each formed from, forexample, silicon oxide; a first diffusion-preventing film 20 and asecond diffusion-preventing film 25, each formed from, for example,silicon carbide; and a third diffusion-preventing film 30 formed from,for example, silicon nitride.

A wiring groove 17 t is disposed in the above-described third insulatingfilm 17, and is filled with a first wiring layer formed by, for example,a damascene process and composed of a barrier metal layer 18 formed fromtantalum/tantalum oxide and an electrically conductive layer 19 formedfrom copper.

Likewise, a second wiring layer composed of a barrier metal layer 23 andan electrically conductive layer 24 is disposed in a wiring groove 22 tin the fifth insulating film 22. A wiring groove 27 t is disposed in theseventh insulating film 27, and a third wiring layer composed of abarrier metal layer 28 and an electrically conductive layer 29 isdisposed therein. The above-described first to thirddiffusion-preventing films prevent diffusion of copper constituting theelectrically conductive layers (19, 24, 29).

In this manner, wiring layers are embedded in the above-describedinsulating films laminated. Each of the above-described first to thirdwirings may have a wiring structure formed integrally with a contactportion in a opening portion from a bottom of the wiring groove to alower layer wiring by, for example, a dual damascene process.

In the pad electrode region R_(PAD), a pad electrode 32 is disposed as alayer on the insulating film. The pad electrode 32 is formed from, forexample, aluminum and is connected to the third wiring or the likethrough an opening portion 31c or the like disposed in the eighthinsulating film 31 or the like. Regarding the size, for example, thediameter is about 100 pi.

Furthermore, a ninth insulating film 33 formed from silicon oxide isdisposed all over the surface while covering the above-described padelectrode 32.

For example, in a portion above the photodiode PD, a concave portion His disposed in the fourth to ninth insulating films and the first tothird diffusion-preventing films formed by lamination as describedabove.

The insulating films laminated on the photodiode PD are configured toinclude the diffusion-preventing film of the wiring layer, as describedabove. For example, the first diffusion-preventing film 20 serving asthe lowermost diffusion-preventing film constitutes the bottom of theconcave portion H.

The above-described concave portion H has, for example, an openingdiameter of about 0.8 μm and an aspect ratio of about 1 to 2 or moredepending on the area and the pixel size of the photodiode, processrules, and the like.

For example, an inner wall of the concave portion H is a surfaceperpendicular to a main surface of the substrate, and a part of theninth insulating film 33 serving as an edge part of the concave portionH is a reverse tapered opening shaped portion 33 a which is divergentupwardly.

A passivation film 36 which covers the inner wall of the above-describedconcave portion H and which has a refractive index higher than that ofsilicon oxide (refractive index 1.45) is disposed as a layer above thepad electrode 32. The passivation film 36 is formed from, for example,silicon nitride (refractive index 2.0) and has a film thickness of about0.5 μm.

For example, although the edge part of the opening takes the reversetapered shape, regarding the profile, deposition is thick at the openingedge portion and deposition is thin in the vicinity of the bottom of theconcave portion H due to the anisotropy during deposition.

For example, a core layer 37 having a refractive index higher than therefractive index of silicon oxide is disposed as a layer on thepassivation film 36 while being filled in the concave portion H. Thecore layer 37 is filled in the concave portion H, and the film thicknessoutside the concave portion H is about 0.5 μm.

The core layer 37 is composed of a high-refractive index resin, e.g., asiloxane based resin (refractive index 1.7) or polyimide. The siloxanebased resin is particularly preferable.

Furthermore, the above-described resin contains metal oxide fineparticles of, e.g., titanium oxide, tantalum oxide, niobium oxide,tungsten oxide, zirconium oxide, zinc oxide, indium oxide, or hafniumoxide, so as to increase the refractive index.

A planarizing resin layer 38 also functioning as, for example, anadhesive layer is disposed as a layer on the above-described core layer37. Color filters (39 a, 39 b, 39 c) of, for example, blue (B), green(G), and red (R), respectively, are disposed thereon on a pixel basis,and a microlens 40 is disposed thereon.

No color filter is disposed in the pad electrode region R_(PAD). Theninth insulating film 33, the passivation film 36, the core layer 37,the planarizing resin layer 38, and a resin layer 40 a constituting themicrolens are laminated as layers on the pad electrode 32, and anopening P is disposed in such a way as to expose an upper surface of thepad electrode 32.

FIG. 2 is a schematic layout diagram of a pixel portion of thesolid-state image pickup device according to the present embodiment.

The passivation film 36 and the core layer 37, which are formed from thehigh-refractive index substance and which are filled in the concaveportion H, constitute an optical waveguide for guiding the lightincident from the outside to the photodiode.

For example, the optical waveguide is disposed in a region smaller thanthe region of the photodiode PD.

The wiring layers, e.g., the first to third wiring layers as shown inFIG. 1 are disposed in the insulating films in such a way as to take theshape of a mesh surrounding the concave portion H. The term “shape of amesh” indicates a state in which the wiring layers and the insulatingfilms are vertically alternatively laminated. For example, the region ofthe concave portion H is set in the region surrounded by the wiringlayers (W1, W2) extending in the vertical direction and the wiringlayers (W3, W4) extending in the horizontal direction. Each of thewiring layers (W1, W2, W3, W4) has, for example, a structure in theshape of a mesh.

FIG. 3 is a schematic sectional view for explaining a route of lightincident on the photodiode of the solid-state image pickup deviceaccording to the present embodiment.

For example, the light L incident by the route as shown in FIG. 3 entersobliquely and, therefore, does not enter the photodiode PD of the pixel,on which the light L is incident, but enters an adjacent pixel so as tocause color mixing.

However, in the case where the above-described mesh-shaped wiring layersare disposed around the above-described optical waveguide, the light,which is likely to leak to the adjacent pixel, is reflected and,thereby, entrance into the photodiode of the adjacent pixel can beprevented.

Furthermore, for example, as shown in FIG. 2, in the case where theregion of the concave portion H is laid out in the region surrounded bythe above-described wiring layers (W1, W2, W3, W4), it is preferablethat the area is not overlapped with the wiring layers (W1, W2, W3, W4)and is set at the maximum in order to increase the incident efficiencyof the light.

However, in the above-described wiring layers (W1, W2, W3, W4), regions(W1 a, W3 a, W4 a, W4 b) protruding toward the region for the concaveportion H are usually present. Therefore, the region for the concaveportion H needs to avoid these regions.

In the present embodiment, layout is performed in such a way that theshape of cross-section of the concave portion H in a plane parallel to amain surface of the semiconductor substrate takes an angular and/orcurved shape having simply outward-convex components in the regionavoiding the above-described protrusion regions of the wiring layers.

Here, an angular shape having simply outward-convex components refers tothe angular shape having interior angles not exceeding 180 degrees,where angular shapes, in which a corner edge is rounded, are alsoincluded.

A curved shape having simply outward-convex components refers to thecurved shape, in which every tangent at all points on the curve does notcross the shape and always present outside the shape except the point ofcontact, where a circle, an ellipse, and the like are included.

The shape may be a combination of a part of the angular shape havingsimply outward-convex components and a part of the curved shape havingsimply outward-convex components.

In the present embodiment, preferably, the area of the concave portion Hsatisfying the above-described constraint that the shape has simplyoutward-convex components is set at the maximum without overlapping thewiring layers which are embedded in the insulating films in such a wayas to surround the concave portion.

FIGS. 4A to 4G are schematic diagrams showing examples of the shapes ofconcave portions H of the solid-state image pickup device according tothe first embodiment of the present invention. The inside of the angularshape is diagonally shaped.

FIG. 4A shows an angular shape A having an interior angle of about 45degrees that does not exceed 180 degrees. FIG. 4B shows an angular shapeB which is the angular shape shown in FIG. 4A having a rounded corneredge.

FIG. 4C shows an angular shape C having an interior angle of about 90degrees that does not exceed 180 degrees. FIG. 4D shows an angular shapeD which is the angular shape shown in FIG. 4C having a rounded corneredge.

FIG. 4E shows an angular shape E having an interior angle of about 135degrees that does not exceed 180 degrees. FIG. 4F shows an angular shapeF which is the angular shape shown in FIG. 4E having a rounded corneredge.

The shape is allowed to have simply outward-convex components, asdescribed above.

On the other hand, an angular shape G as shown in FIG. 4G has aninterior angle exceeding 180 degrees. Such a shape does not have simplyoutward-convex components. A shape having such an angular shape is notadopted in the present invention.

For example, if an inward-convex angular shape is present, crackingeasily occurs from such a point in the high-refractive index resin,e.g., a siloxane based resin, filled in the concave portion H.

Therefore, by allowing the shape of the concave portion H to take anangular and/or curved shape having simply outward-convex components, asdescribed above, an occurrence of cracking in the core layer 37 filledin the concave portion H can be suppressed, and deterioration of thesensitivity and an occurrence of noise can be reduced.

In the above-described solid-state image pickup device according to anembodiment of the present invention, the concave portion H is disposedabove the photodiode and in the insulating film disposed as the layer onthe photodiode, and the optical waveguide is constructed by filling theconcave portion H with the high-refractive index substance. Thepassivation film disposed as the layer on the pad electrode is also usedas the high-refractive index substance filled in the concave portion.Consequently, the configuration can be produced by a simpler processeven when the optical waveguide is disposed.

In the solid-state image pickup device according to an embodiment of thepresent invention, for example, logic circuits and the like can bemounted together on the same chip. In this case, the above-describedpassivation film constituting the optical waveguide is also used as apassivation film in the logic and other regions.

According to the solid-state image pickup device according to anembodiment of the present invention, since the optical waveguidestructure is adopted as described above, the sensitivity is increased,and shading can be reduced. Furthermore, the color mixingcharacteristics can be improved by using the wiring layers aslight-shielding film patterns for adjacent pixels.

A method for manufacturing a solid-state image pickup device accordingto an embodiment of the present invention will be described below withreference to the drawings.

As shown in FIG. 5A, for example, in the pixel region R_(PX), an n-typecharge-storage layer 11 and a p⁺-type surface layer 12, which is asurface layer of the n-type charge-storage layer, are formed in a p-wellregion 10 of a semiconductor substrate, so as to constitute a photodiodePD having pn junction. A gate insulating film 13, a gate electrode 14,and a signal transferring portion, e.g., floating diffusion and a CCDcharge transfer line, for reading signal charges generated and stored inthe photodiode or voltages corresponding to the signal charges areformed adjacently to the photodiode PD.

For example, silicon oxide is deposited by a chemical vapor deposition(CVD) method all over the pixel region R_(PX) and the pad electroderegion R_(PAD) while covering the photodiode PD so as to form the firstinsulating film 15.

For example, silicon oxide is deposited as a layer on the firstinsulating film 15 so as to form the second insulating film 16, andsilicon oxide is further deposited so as to form the third insulatingfilm 17.

For example, a wiring groove 17 t is formed in the third insulating film17 by etching. Furthermore, a film of tantalum/tantalum oxide is formedcovering the inner wall of the wiring groove 17 t by sputtering so as toform the barrier metal layer 18. A copper seed layer is formed, a filmof copper is formed all over the surface by an electrolytic platingtreatment, and copper formed outside the wiring groove 17 t is removedby a chemical mechanical polishing (CMP) method or the like so as toform the electrically conductive layer 19. At this time, the barriermetal layer 18 formed outside the wiring groove 17 t is also removed. Inthis manner, the first wiring layer composed of barrier metal layer 18and the electrically conductive layer 19 filled in the wiring groove 17t is formed.

For example, silicon carbide is deposited as a layer on the first wiringlayer by the CVD method so as to form the first diffusion-preventingfilm 20.

As shown in FIG. 5B, the above-described process for forming the secondinsulating film 16, the third insulating film 17, the wiring groove 17t, the second wiring layer composed of the barrier metal layer 18 andthe electrically conductive layer 19, and the first diffusion-preventingfilm 20 is repeated and, thereby, for example, the fourth insulatingfilm 21, the fifth insulating film 22, the wiring groove 22 t, thebarrier metal layer 23, the electrically conductive layer 24, and thesecond diffusion-preventing film 25 are formed. Furthermore, the sixthinsulating film 26, the seventh insulating film 27, the wiring groove 27t, the third wiring layer composed of the barrier metal layer 28 and theelectrically conductive layer 29 are formed. Silicon nitride is furtherdeposited by, for example, the CVD method so as to form the thirddiffusion-preventing film 30. Moreover, the eighth insulating film 31 isformed as a layer thereon.

As described above, the insulating film, in which the first insulatingfilm 15, the second insulating film 16, the third insulating film 17,the fourth insulating film 21, the fifth insulating film 22, the sixthinsulating film 26, the seventh insulating film 27, and the eighthinsulating film 31; the first diffusion-preventing film 20 and thesecond diffusion-preventing film 25, each formed from, for example,silicon carbide; and the third diffusion-preventing film 30 formed from,for example, silicon nitride are laminated, and the first to thirdwiring layers, which are embedded in the insulating films, are formed.

Here, the above-described third wiring layer is formed in such a way asto extend to the pad electrode region R_(PAD).

For each of the above-described first to third wirings, a wiringstructure may be formed integrally with the contact portion in theopening portion from the bottom of the wiring groove to the lower layerwiring by, for example, a dual damascene process.

As shown in FIG. 6A, the opening portion 31c reaching the third wiringlayer is formed in the eighth insulating layer 31 and the like. A filmof aluminum is formed by a sputtering method or the like at a filmformation temperature of, for example, about 300° C. and, thereafter,patterning is performed so as to form the pad electrode 32 having adiameter of, for example, about 100 μm.

All the steps after formation of the aluminum pad electrode 32 areallowed to be processes at 400° C. or lower.

As shown in FIG. 6B, for example, silicon oxide is deposited all overthe pixel region R_(PX) and the pad electrode region R_(PAD) by the CVDmethod while covering the pad electrode 32 so as to form the ninthinsulating film 33.

As shown in FIG. 7, for example, a resist film 34 with a pattern foropening the concave portion H is patterned by a photolithography step,and etching, e.g., chemical dry etching or other isotropic etching,anisotropic etching, or the like is performed so as to form the reversetapered opening shaped portion 33 a, which is divergent upwardly, in theninth insulating film 33.

The above-described resist film 34 is removed. As shown in FIG. 8, forexample, a resist film 35 with the same pattern as that of the resistfilm 34 is formed by patterning. Anisotropic etching, e.g., reactive ionetching is performed so as to form the concave portion H in the fourthto ninth insulating films and the first to third diffusion-preventingfilms.

In opening the above-described concave portion H, for example, etchingis allowed to proceed while the condition is changed depending on thematerials, e.g., silicon oxide, silicon nitride, and silicon carbide,and when the bottom of the opening reaches the firstdiffusion-preventing film 20, etching is allowed to stop promptly.

In this manner, the first diffusion-preventing film 20 is allowed toconstitute the bottom of the concave portion H.

Since the first diffusion-preventing film 20 serves as the bottom of theconcave portion H, as described above, the depth of the concave portionH can be determined stably. Consequently, the distance between thephotodiode and the optical waveguide becomes constant and, thereby,occurrence of variations in the characteristics can be prevented.

As described above, the concave portion H can be opened. For example,the opening diameter is about 0.8 μm, the aspect ratio is about 1 to 2or more, and the edge part of the concave portion H is a part of theninth insulating film 33 and is a reverse tapered opening shaped portion33 a.

As shown in FIG. 9, silicon nitride having a refractive index higherthan that of silicon oxide is deposited as a layer above the padelectrode 32 while covering the inner wall of the concave portion H by,for example, a plasma CVD method at a film formation temperature ofabout 380° C., so as to form the passivation film 36 having a filmthickness of about 0.5 μm. The edge part of the opening takes thereverse tapered shape. However, regarding the profile, deposition isthick at the opening edge portion and deposition is thin in the vicinityof the bottom of the concave portion H due to the anisotropy duringdeposition.

As shown in FIG. 10, a film of siloxane based resin containing metaloxide fine particles, e.g., titanium oxide, and having a film thicknessof about 0.5 μm is formed by, for example, a spin coating method at afilm formation temperature of about 400° C., and is filled in theconcave portion H as a layer on the passivation film 36, so as to formthe core layer 37 having a refractive index higher than that of siliconoxide. After coating, for example, a post bake treatment is performed atabout 300° C., if necessary. In the case where a polyimide resin isused, a film can be formed at a temperature of, for example, about 350°C.

As shown in FIG. 11, the planarizing resin layer 38 also functioning as,for example, an adhesive layer is formed as a layer on the core layer37. Color filters (39 a, 39 b, 39 c) of, for example, blue (B), green(G), and red (R), respectively, are formed as a layer thereon on a pixelbasis.

The microlens 40 is further formed as a layer thereon.

In the above-described manufacturing method, a hydrogen treatment(sintering) for terminating dangling bonds in the semiconductor can beperformed in any step, for example, after the forming of pad electrodeand before the filling of resin core layer.

Furthermore, as shown in FIG. 1, in the pad electrode region R_(PAD), anopening P is formed in such a way as to expose the upper surface of thepad electrode 32.

In this manner, the solid-state image pickup device having theconfiguration as shown in FIG. 1 can be produced.

In the method for manufacturing a solid-state image pickup deviceaccording to the present embodiment, the passivation film formed as thelayer on the pad electrode is also used as the high-refractive indexsubstance to be filled in the concave portions H. Therefore, theproduction can be performed by a simpler process even when the opticalwaveguide is disposed.

Second Embodiment

FIG. 12 is a schematic sectional view showing the configuration of a CMOsensor which is a solid-state image pickup device according to anembodiment of the present invention.

For example, a sensor portion 102 including a light-receiving portion101 for photoelectric conversion of light and a first insulating film109, which covers the light-receiving portion 101 and which is formedfrom, for example, silicon oxide, are disposed on a semiconductorsubstrate 100. A second insulating film 120, a third insulating film121, a fourth insulating film 123, and a fifth insulating film 125,which are formed from, for example, silicon oxide, are disposed on thissensor portion 102. A first wiring layer 131, a second wiring layer 133,and a third wiring layer 135, each formed by, for example, a damasceneprocess and composed of a barrier metal layer, although not shown in thedrawing, formed from tantalum/tantalum oxide and copper, are disposed inthese second insulating film 120, third insulating film 121, fourthinsulating film 123, and fifth insulating film 125. The first wiringlayer 131 is electrically connected to the light-receiving portion 101through a contact plug 130 formed by, for example, the damasceneprocess, and each wiring is electrically connected to each other througha first via plug 132 and a second via plug 134 formed by, for example,the damascene process. A first diffusion-preventing film 122 and asecond diffusion-preventing film 124, which are formed from, forexample, silicon carbide having a film thickness of about 50 nm, aredisposed between the third insulating film 121, the fourth insulatingfilm 123, and the fifth insulating film 125. A thirddiffusion-preventing film 126 formed from, for example, silicon nitrideis disposed on the fifth insulating film 125. Consequently, diffusion ofcopper constituting the first wiring layer 131, the second wiring layer133, and the third wiring layer 135 is prevented.

The above-described first to third wiring (131, 133, 135) may be wiringstructures formed integrally with the contact plug 130, the first viaplug 132, and the second via plug 134, respectively, by the damasceneprocess, for example.

The light-receiving portion 101 is composed of, for example, a gateinsulating film 103 formed from silicon oxide, a gate electrode 104formed from polysilicon, and insulating films (105, 106, 107, 108)formed from silicon nitride.

A sixth insulating film 127 formed from silicon oxide and a seventhinsulating film 128 serving as a protective film are disposed on thethird diffusion-preventing film 126.

Here, for example, in the portion above the light-receiving portion 101,a concave portion K is disposed in the third insulating film 121, thefourth insulating film 123, the fifth insulating film 125, the sixthinsulating film 127, and the seventh insulating film 128; and the firstdiffusion-preventing film 122, the second diffusion-preventing film 124,and the third diffusion-preventing film 126 between the insulatingfilms, which are disposed by lamination as described above.

The above-described concave portion K has, for example, an openingdiameter of about 0.8 μm and an aspect ratio of about 1 to 2 or moredepending on the area and the pixel size of the light-receiving portion101, process rules, and the like.

For example, a core layer 140 composed of an inorganic substance havingthe heat resistance higher than the heat resistance of a TiO-dispersionorganic resin and a metal oxide is disposed while being filled in theconcave portion K. The core layer 140 serves as an optical waveguide.The inside of the concave portion K is filled with the core layer 140.

The core layer 140 is formed from an inorganic substance, for example,an oxide, e.g., silicon oxide, which has high heat resistance and whichcontains metal oxide fine particles of, e.g., titanium oxide, tantalumoxide, niobium oxide, tungsten oxide, zirconium oxide, zinc oxide,indium oxide, or hafnium oxide through ion-implantation. In particular,silicon oxide is preferable as the inorganic substance and titaniumoxide is preferable as the metal oxide.

A planarizing resin layer 160 also functioning as, for example, anadhesive layer formed from an acrylic thermosetting resin or the like isdisposed as a layer on the above-described core layer 140. A colorfilter 161 is disposed as a layer thereon, and a microlens 162, which isan optical element for condensing the incident light, is disposed as alayer thereon.

In the CMOS sensor having the above-described configuration, theincident light is condensed by the microlens 162, and is applied to thelight-receiving portion 101 through the core layer 140 serving as theoptical waveguide formed from the inorganic substance and the metaloxide, so as to be subjected to photoelectric conversion in thelight-receiving portion 101.

A method for manufacturing a solid-state image pickup device accordingto an embodiment of the present invention will be described below withreference to the drawings.

As shown in FIG. 13, a gate insulating film 103 formed from siliconoxide and a gate electrode 104 formed from polysilicon are formed as thelight-receiving portion 101 on the semiconductor substrate 100. Theinsulating films (105, 106, 107, 108) formed from silicon nitride areformed above them.

Silicon oxide is deposited all over the light-receiving portion 101 by,for example, CVD so as to form the first insulating film 109 is formedon the light-receiving portion 101 and, thereby, the sensor portion 102is produced.

Silicon oxide is deposited by CVD or the like so as to form the secondinsulating film 120 and the third insulating film 121. A groove for thecontact plug 130 is formed in the second insulating film 120 and thethird insulating film 121 by etching. A film of tantalum/tantalum oxideis formed covering the inner wall of the groove for the contact plug 130by sputtering so as to form a barrier metal layer, although not shown inthe drawing. A copper seed layer is formed, and a film of copper isformed all over the surface by an electrolytic plating treatment, so asto form the contact plug 130.

A groove for the first wiring layer 131 is formed on the contact plug130. Furthermore, a film of tantalum/tantalum oxide is formed coveringthe inner wall of the groove for the first wiring layer 131 bysputtering so as to form a barrier metal layer, although not shown inthe drawing. A copper seed layer is formed, a film of copper is formedall over the surface by an electrolytic plating treatment, and copperformed outside the groove for the first wiring layer 131 is removed by achemical mechanical polishing (CMP) method or the like, so as to formthe first wiring layer 131. In this manner, the contact plug 130 and thefirst wiring layer 131 are formed.

Silicon carbide is deposited as a layer on the first wiring layer 131by, for example, CVD so as to form the first diffusion-preventing film122.

Silicon oxide is deposited all over the first diffusion-preventing film122 by using, for example, tetra ethyl ortho silicate (TEOS) through CVDor the like so as to form the fourth insulating film 123.

The above-described process for forming the second insulating film 120,the third insulating film 121, the fourth insulating film 123, thecontact plug 130, the first wiring layer 131, and the firstdiffusion-preventing film 122 is repeated and, thereby, the first viaplug 132, the second wiring layer 133, and the seconddiffusion-preventing film 124 are formed. Furthermore, the fifthinsulating film 125, the second via plug 134, the third wiring layer135, the third diffusion-preventing film 126, and the sixth insulatingfilm 127 are formed. The seventh insulating film 128 formed from siliconoxide is formed thereon through, for example, CVD.

As described above, the second insulating film 120, the third insulatingfilm 121, the fourth insulating film 123, the fifth insulating film 125,the sixth insulating film 127, and the seventh insulating film 128; thefirst diffusion-preventing film 122 and the second diffusion-preventingfilm 124, each formed from, for example, silicon carbide and disposedbetween the insulating films; the third diffusion-preventing film 126formed from, for example, silicon nitride, and disposed between theinsulating films; the first to third wiring layers (131, 133, 135),which are embedded in the insulating films; and the first via plug 132and the second via plug 134 are formed.

The above-described first to third wirings (131, 133, 135) may be wiringstructures formed integrally with the contact plug 130, the first viaplug 132, and the second via plug 134, respectively, in the openingportion from the bottom of the wiring groove to the lower layer wiringby, for example, the dual damascene process.

As shown in FIG. 14, for example, a resist film 150 with a pattern foropening the concave portion K is patterned by a photolithography step,and anisotropic etching, e.g., reactive ion etching, is performed so asto form the concave portion K in the second to seventh insulating films(120, 121, 123, 125, 127, 128) and the first to thirddiffusion-preventing films (131, 133, 135). For example, etching isallowed to proceed while the condition is changed depending on thematerials, e.g., silicon oxide, silicon nitride, and silicon carbide.

As shown in FIG. 15, the above-described resist film 150 is removed, andthe inorganic substance having the heat resistance higher than that ofthe TiO-dispersion organic resin is filled in the concave portion K by,for example, a spin coating method at a film formation temperature ofabout 400° C., so as to form the core layer 140. Examples of inorganicsubstances to be filled in the concave portion K include oxides, e.g.,silicon oxide. Subsequently, the inorganic substance deposited on theseventh insulating film 128 is polished by a chemical mechanicalpolishing (CMP) method or the like, so that planarization is performed.

As shown in FIG. 16, for example, a resist film 151 with a pattern foropening the concave portion K is patterned by a photolithography step insuch a way that merely the concave portion K is exposed. The metal oxideis ion-implanted by using the resist film 151 as a mask and, thereby,the metal oxide is contained in merely the inorganic substance filled inthe concave portion K.

The planarizing resin layer 160 also functioning as, for example, anadhesive layer formed from an acrylic thermosetting resin or the like isformed as the layer on the above-described core layer 140. For example,the color filter 161 is formed as the layer thereon, so that thesolid-state image pickup device having the configuration as shown inFIG. 12 is produced.

Furthermore, the microlens 162 is formed as the layer thereon.

Although not shown in the drawing, a plurality of light-receivingportions 101 are disposed in a matrix on the semiconductor substrate100, and the color (one of three primary colors) of the color filter 161corresponds to the color of the corresponding light-receiving portion101.

Third Embodiment

FIG. 17 is a schematic configuration diagram of a camera according tothe present embodiment.

A solid-state image pickup device 50 having a plurality of pixelsintegrated, an optical system 51, and a signal processing circuit 53 areincluded.

In the present embodiment, the above-described solid-state image pickupdevice 50 is set by incorporating the solid-state image pickup deviceaccording to any one of the above-described first to third embodiments.

The optical system 51 forms an image on the basis of the light of imagefrom the subject (incident light) on a image pickup surface of thesolid-state image pickup device 50. Consequently, conversion to a signalcharge is performed in accordance with the amount of the incident lightin the photodiode constituting each pixel on the image pickup surface ofthe solid-state image pickup device 50, and the resulting signal chargeis stored for a predetermined time.

The stored signal charge is passed through, for example, a CCD chargetransfer line, and is taken out as an output signal Vout.

The signal processing circuit 53 subjects the output signal Vout of thesolid-state image pickup device 50 to various types of signal processingand outputs as an image signal.

According to the above-described camera of the present embodiment, colorshading characteristics and dispersion characteristics can be improvedwithout causing reduction of condensation rate of the obliquely incidentlight and deterioration of sensitivity. Furthermore, a microlens can beformed by a simple method and process.

The present invention is not limited to the above-described explanation.

For example, according to the embodiments, the present invention can beapplied to both the MOS sensor and the CCD element.

It should be understood by those skilled in the art that variousmodifications, combinations, sub-combinations and alterations may occurdepending on design requirements and other factors insofar as they arewithin the scope of the appended claims or the equivalents thereof.

1. A solid-state image pickup device having a plurality of pixelsintegrated on a light-receiving surface, said device comprising:photodiodes (a) which are disposed in pixel regions serving as thelight-receiving surface of a semiconductor substrate and (b) which arepartitioned on the pixel basis; signal transferring portions (a) whichare disposed on the semiconductor substrate and (b) which read signalcharges generated and stored in the photodiodes or voltagescorresponding to the signal charges; insulating films disposed over thesemiconductor substrate and covering the photodiodes; concave portionsdisposed in portions of the insulating films above the photodiodes; anda core layer (a) which is disposed within the concave portions and fillsthe concave portions and (b) which contains an inorganic substance thatfills the concave portion, and a metal oxide, the metal oxide comprisingtitanium oxide, tantalum oxide, niobium oxide, tungsten oxide, zirconiumoxide, zinc oxide, indium oxide, or hafnium oxide.
 2. The solid-stateimage pickup device according to claim 1, wherein the photodiodes havesides defined by the portions of the insulating films.
 3. Thesolid-state image pickup device according to claim 1, wherein the metaloxide is ion-implanted into the inorganic substance.
 4. The solid-stateimage pickup device according to claim 1, wherein the core layer has aheat resistance higher than the heat resistance of a TiO-dispersionorganic resin.
 5. The solid-state image pickup device according to claim1, wherein the inorganic substance comprises silicon oxide.
 6. Thesolid-state image pickup device according to claim 1, wherein aplanarizing resin layer is formed on the core layer, the planarizingresin layer being in contact with the core layer.
 7. A method formanufacturing a solid-state image pickup device having a plurality ofpixels integrated on a light-receiving surface, the method comprisingthe steps of: forming (a) photodiodes in pixel regions serving as thelight-receiving surface of a semiconductor substrate, the photodiodesbeing partitioned on the pixel basis, and (b) signal transferringportions for reading signal charges generated and stored in thephotodiodes or voltages corresponding to the signal charges; forminginsulating films over the semiconductor substrate, the insulating filmscovering the photodiodes; forming concave portions in portions of theinsulating films above the photodiodes; forming a core layer by fillingthe concave portions with an inorganic substance; and ion-implanting ametal oxide into the inorganic substance.
 8. The method of claim 7,wherein the photodiodes have sides are defined by the portions of theinsulating films
 9. The method of claim 7, wherein, the core layer hasthe heat resistance higher than the heat resistance of a TiO-dispersionorganic resin.
 10. The method of claim 7, wherein silicon oxide is usedas the inorganic substance in the forming a core layer.
 11. The methodof claim 7, wherein titanium oxide, tantalum oxide, niobium oxide,tungsten oxide, zirconium oxide, zinc oxide, indium oxide, or hafniumoxide is used as the metal oxide in the ion-implanting.
 12. The methodaccording to claim 4, further comprising forming a planarizing resinlayer on the core layer, the planarizing resin layer being in contactwith the core layer.
 13. A solid-state image pickup device having aplurality of pixels integrated on a light-receiving surface, said devicecomprising: photodiodes (a) which are disposed in pixel regions servingas the light-receiving surface of a semiconductor substrate and (b)which are partitioned on the pixel basis; signal transferring portions(a) which are disposed on the semiconductor substrate and (b) which readsignal charges generated and stored in the photodiodes or voltagescorresponding to the signal charges; insulating films disposed over thesemiconductor substrate and covering the photodiodes; concave portionsdisposed in portions of the insulating films above the photodiodes; acore layer (a) which is disposed within the concave portions and fillsthe concave portions and (b) which contains an inorganic substance thatfills the concave portion, and a metal oxide; and a planarizing resinlayer over the core layer, the planarizing resin layer being in contactwith the core layer.
 14. The solid-state image pickup device accordingto claim 13, wherein the inorganic substance comprises silicon oxide.15. The solid-state image pickup device according to claim 13, whereinthe metal oxide comprises titanium oxide, tantalum oxide, niobium oxide,tungsten oxide, zirconium oxide, zinc oxide, indium oxide, or hafniumoxide.
 16. A method for manufacturing a solid-state image pickup devicehaving a plurality of pixels integrated on a light-receiving surface,the method comprising the steps of: forming (a) photodiodes in pixelregions serving as the light-receiving surface of a semiconductorsubstrate, the photodiodes being partitioned on the pixel basis, and (b)signal transferring portions for reading signal charges generated andstored in the photodiodes or voltages corresponding to the signalcharges; forming insulating films on the semiconductor substrate, theinsulating films covering the photodiodes; forming concave portions inportions of the insulating films above the photodiodes; and forming acore layer by filling the concave portions only with an inorganicsubstance.
 17. The method for manufacturing a solid-state image pickupdevice according to claim 16, wherein silicon oxide is used as theinorganic substance in the forming a core layer.
 18. The method formanufacturing a solid-state image pickup device according to claim 16,wherein titanium oxide, tantalum oxide, niobium oxide, tungsten oxide,zirconium oxide, zinc oxide, indium oxide, or hafnium oxide is used asthe metal oxide in the ion-implanting.